The influence of silencing of NF-κB gene on the proliferation of gastric cancer cells exposed to hypoxia and its mechanism / 肿瘤

ABSTRACT

Objective: To investigate the influence of nuclear factor-κB (NF-κB) gene silence on the proliferation of gastric cancer SGC-7901 cells exposed to hypoxia and its possible mechanism. Methods: SGC-7901 cells were transfected with recombinant vector pcDNA™ 6.2-GW/EmGFPmiR-NF-κB in which the NF-κB was silenced, and the stably transfected cell line SGC-7901 was screened out. There are four groups were designed in this study: control group (SGC-7901 cells were cultured under normoxic conditions), hypoxic group (SGC-7901 cells were cultured under hypoxic conditions), transfection group (SGC-7901 cells were transfected with recombinant vector pcDNA™ 6.2-GW/EmGFPmiR-NF-κB and cultured under normoxic conditions) and combination group (SGC-7901 cells were transfected with recombinant vector pcDNA™6.2-GW/EmGFPmiR-NF-κB and cultured under hypoxic conditions). The viability of SGC-7901 cells in each group was detected by Trypan blue staining. The colony-formation assay and cell doubling time assay were used to examine the proliferation of SGC-7901 cells. The expression levels of NF-κB, hypoxia-inducible factor-1α (HIF-1α) and phospholipase D1 (PLD1) proteins in SGC-7901 cells were examined by Western blotting. Results: The SGC-7901 cells were successfully transfected with recombinant vector pcDNA™6.2-GW/EmGFPmiR-NF-κB, and the stably transfected cell line was established. As compared with the control group, the viabilities of SGC-7901 cells in the transfection group and the combination group were obviously decreased (P < 0.05), but there was no significant change in the hypoxic group. As compared with the control group, the colony-forming number of SGC-7901 cells in the hypoxic group was increased and the cell doubling time was shortened (P < 0.05), while the numbers of colony-forming in the transfection group and combination group were decreased and the cell doubling time was prolonged (P < 0.05). The expression levels of NF-κB, HIF-1α and PLD1 proteins in SGC-7901 cells in the transfection group were obviously suppressed, while these expressions in the hypoxic group were obviously up-regulated (P < 0.05). As compared with the hypoxic group, the expression levels of NF-κB, HIF-1α and PLD1 proteins in SGC-7901 cells in the combination group were significanly down-regulated (P < 0.05). Conclusion: In SGC-7901 cells exposed to hypoxic conditions, there may be an interaction between HIF-1α and NF-κB. The suppression of NF-κB expression can inhibit the proliferative ability of gastric cancer SGC-7901 cells under hypoxic conditions via down-regulation of HIF-1α and PLD-1 expressions Copyright© 2014 by TUMOR.